Field of the Invention
This invention relates to a scanning apparatus that scans a sample, a confocal observation apparatus that includes the scanning apparatus, and a disk scanning apparatus.
Description of the Related Art
Confocal observation apparatuses such as a confocal microscope are widely used in various fields such as a testing of a semiconductor substrate and an observation of a biological sample because they have a high resolution in a Z-axis direction and provide an excellent sectioning effect.
A confocal microscope detects light from each point on a sample such as a substrate or a biological sample by scanning the sample, so as to obtain an image of the sample. For that reason, it includes a scanning apparatus that scans the sample. There are various types of scanning apparatuses for a confocal microscope, and a scanning apparatus that scans a sample by modulating light in a plane optically conjugate with the sample is known. This type of scanning apparatus includes a scanner that uses a micro electromechanical systems (MEMS) device such as a digital micromirror device (DMD) or uses a liquid crystal device, and a scanning apparatus that includes a spinning disk in which, for example, slits or pinholes are formed (hereinafter referred to as “disk scanning apparatus”) is a typical example of it.
Generally, using a disk scanning apparatus, multipoint scanning can be performed and there are fewer mechanical restrictions on a high-speed rotation of a disk. Thus, in principle, a sample can be scanned at high speed. However, in the disk scanning apparatus, a majority of incident illumination light is interrupted and wasted by the disk. As a result, an exposure time is increased in order to compensate its low illumination efficiency, and in reality, it is difficult to realize a high-speed scanning of a sample.
For example, Japanese Laid-open Patent Application Publication No. 04-330412, US Patent Application Publication No. 2008/0218849, and Japanese Laid-open Patent Application Publication No. 2013-015681 disclose technologies related to such a problem. Those three documents disclose technologies that improve an illumination efficiency of a disk scanning apparatus.